From 72400f8d50869f50a54b67146b17acaab0fcb16f Mon Sep 17 00:00:00 2001 From: Michael Kuperstein Date: Thu, 16 Jul 2015 12:27:59 +0000 Subject: [PATCH] [X86] Fix emitPrologue() to make less assumptions about pushes When X86FrameLowering::emitPrologue() looks for where to insert the %esp subtraction to allocate stack space for local allocations, it assumes that any sequence of push instructions that starts at function entry consists purely of spills of callee-save registers. This may be false, since from some point forward, the pushes may pushing arguments to a subsequent function call. This caused a miscompile that was exposed by r240257, and is not easily testable since r240257 was reverted. A test will be committed separately after r240257 is reapplied. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242395 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/X86FrameLowering.cpp | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp index 2a35c4cf31f..edbe7d0894a 100644 --- a/lib/Target/X86/X86FrameLowering.cpp +++ b/lib/Target/X86/X86FrameLowering.cpp @@ -794,6 +794,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF, int StackOffset = 2 * stackGrowth; while (MBBI != MBB.end() && + MBBI->getFlag(MachineInstr::FrameSetup) && (MBBI->getOpcode() == X86::PUSH32r || MBBI->getOpcode() == X86::PUSH64r)) { PushedRegs = true; -- 2.34.1